The present invention relates to an arrangement for filling cavities of structures in general, and more particularly to an arrangement for filling bulk material into cavities of molds and the like.
There are various constructions of arrangements of this type already known and used. The present invention is concerned with an arrangement of this type which is particularly suited for filling cavities of molds provided in beds or platens of brick presses and the like. In this environment, it is already known to fill the respective cavity, which is upwardly open, by means of a filling receptacle which has an open bottom, and which is mounted for relative movement along the bed or platen in a given direction from a receiving position in which the bulk material is introduced into a feeding receptacle, towards a discharging position in which the open bottom of the feeding receptacle is juxtaposed with the open upper end of the respective cavity for discharge of the bulk material, into the respective cavity, and in which the walls of the feeding receptacle surround an open upper end of the respective cavity on all sides. A bottom wall may be movably mounted in the cavity, for vertical movement towards and away from the open upper end of the cavity.
Arrangements of this type are being used, in many instances, in connection with presses for refractory bricks. The requirements for the shape, accuracy, and quality of these refractory bricks are quite high. But the degree of filling of the mold cavity with ceramic material has a very substantial influence on the shape, accuracy, and quality of manufactured bricks.
In known brick presses of this type, the filled feeding receptacle is displaced from a filling position on the bed of the press over the cavity of the mold, while the bottom wall of the cavity of the mold is at the same elevation as the upper surface of the bed. The bottom wall of the cavity of the mold is constituted by a piston. Thereafter, the piston is lowered, so that the bulk or material to be compressed, in this case, a ceramic material, completely fills the cavity of the mold. At the same time, the feeding receptacle becomes empty. When this operation is terminated, the feeding receptacle is returned to the bed of the press. When this happens, the inner wall of the feeding receptacle which faces forwardly during the return displacement, compacts the ceramic material at, and during the movement over, the side of the cavity of the mold, which faces the same, to a higher degree than that obtained at the opposite side of the cavity during the sliding of the ceramic material into the cavity. This non-uniform compaction of the ceramic material in the cavity remains at least partially in existence during the following compressing operation, during which a further piston acts from above on the ceramic material, and it becomes apparent during the so-called breathing phase undergone by the compacted body, that the geometry of the compacted body, which is originally set by the shape of the cavity of the mold, changes.
Of course, it is conceivable to first let the feeding receptacle proceed further, after the filling of the cavity, in the original direction in which the feeding receptacle has been displaced from its discharging position, until the inner wall of the feeding receptacle which faces forwardly, as considered in the direction of displacement, is displaced beyond the side of the cavity which faces the same, so that a higher degree of compaction is first obtained there. Only thereafter can the return displacement of the feeding receptacle be commenced, so that a respectively higher degree of compaction is obtained at the sides of the cavity which are located opposite one another, as considered in the direction of displacement of the feeding receptacle. However, this alternate mode of operation would have the disadvantageous consequence of a considerable widening of the press at its side which is opposite the side at which the feeding receptacle is being filled. In addition thereto, if this procedure were resorted to, the ceramic material introduced into the cavity would be partially entrained for joint displacement by the outer wall of the feeding receptacle, and that could result, disregarding the possibility of soiling, in malfunctions of different kinds. Thus, any attempt at solving the above-mentioned problem of non-uniform degree of compaction in this manner is capable of only marginally improving the uniformity of compaction. The situation is not any different when the press platen includes a plurality of molds or cavities.